Distribution characteristics of integrons and plasmid-mediated quinolone resistance genes in Klebsiella aerogenes clinical isolates / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To investigate the distribution of integrons and plasmid-mediated quinolone resistance (PMQR) genes in clinical isolates of Klebsiella aerogenes and to analyze the relationship between integrons and bacterial resistance to antimicrobial agents. Methods:Ninety-one Klebsiella aerogenes strains isolated from clinical samples in the Fengxian District Central Hospital from November 2015 to March 2021 were used in this study. Class 1 and class 2 integron-integrase genes ( intI1 and intI2) and PMQR genes were screened by PCR. The types of promoters and gene cassette arrays of variable regions were determined by sequencing. Besides, the relationship between integrons and antimicrobial resistance was analyzed. Results:The resistance rate of the 91 Klebsiella aerogenes isolates to aztreonam was more than 40.00% and the resistance rates to other commonly used antimicrobial agents were less than 35.00%. Among the 91 isolates, 30 carried the intI1 gene, while none of them carried the intI2 gene. Seven class 1 integron gene cassette arrays of variable regions were detected and the gene cassette array of aac(6′)-11 C- &Delta;ereA2- IS1247- aac3- arr- &Delta;ereA2 was detected in Klebsiella aerogenes. PcH1 with weak activity was the predominant variable region promoter of class 1 integrons. The detection rates of intI1-positive and intI1-negative isolates in ICU, neurosurgery and other clinical departments were statistically different ( P<0.05). The resistance rate of intI1-positive isolates to some commonly used antibiotics was significantly higher than that of intI1-negative isolates ( P<0.05). qnrS gene was the prevalent PMQR gene. The detection rates of integrons and PMQR genes in Klebsiella aerogenes isolates was low except for the strains isolated in 2016. Conclusions:Antimicrobial resistance in Klebsiella aerogenes was closely related to integrons. The distribution of integrons in Klebsiella aerogenes strains isolated from different clinical departments was different, and the monitoring of drug-resistant strains should be strengthened in ICU and neurosurgery. The resistance to quinolones in Klebsiella aerogenes strains in this region was mainly related to qnrS gene.